A conventional eyeglass frame of this type is disclosed in Japanese Patent Laid-Open No. Sho. 63-58213, as shown in FIGS. 8 and 9.
Referring to FIG. 8, one end of an end piece 106 which projects from a lens frame 101 is formed as an engagement tube 107, and pin holes 171 are formed in the engagement tube 107 and pin holes 182 are also formed in an engagement stem 181 which projects from the proximal end of a temple 108. The engagement stem 181 of the temple 108 is inserted into the engagement tube 107, and pins 172 are inserted through the commensurate pin holes 171 and 182 of the respective members, and the ends of the pins 172 are secured to the temple 108 by pinching as required. This state is shown in FIG. 8(A).
As shown in FIG. 8(B), after the distal end of the temple 108 has been inserted into the engagement tube 107, the temple 108 may be secured by press-fitting the engagement tube 107.
However, the above-described prior art has the problem that the temple 108 and the engagement tube 107 are difficult to drill or thread and costs increase. In particular, with a process utilizing the threading of an NT alloy (a nickel titanium alloy) material, it is impossible to mass-produce eyeglass frames in practice.
In particular, if parts are damaged when eyeglass parts are fused with an eyeglass frame, repair is difficult.
The NT alloy material also has the problem that, when subjected to cutting such as threading or drilling, the material is easily damaged.